EXPLOSIVE BLAST 4 T - FEMA
EXPLOSIVE BLAST4This chapter discusses blast effects, building damage, injuries, levels of protection, stand-off distance, and predictingblast effects. Specific blast design concerns and mitigationmeasures are discussed in Chapters 2 and 3. Explosive events havehistorically been a favorite tactic of terrorists for a variety of reasons and this is likely to continue into the future. Ingredients forhomemade bombs are easily obtained on the open market as arethe techniques for making bombs. Also, explosive events are easyand quick to execute. Vehicle bombs have the added advantageof being able to bring a large quantity of explosives to the doorstep of the target undetected. Finally, terrorists often attempt touse the dramatic component of explosions, in terms of the sheerdestruction they cause, to generate media coverage in hopes oftransmitting their political message to the public. The DoD, GSA,and DOS have considerable experience with blast effects and blastmitigation. However, many architects and building designers donot have such experience. For additional information on explosive blast, see FEMA 427, Primer for Design of Commercial Buildings toMitigate Terrorist Attacks.4.1BLAST EFFECTSWhen a high order explosion is initiated, a very rapid exothermicchemical reaction occurs. As the reaction progresses, the solidor liquid explosive material is converted to very hot, dense,high-pressure gas. The explosion products initially expand atvery high velocities in an attempt to reach equilibrium with thesurrounding air, causing a shock wave. A shock wave consists ofhighly compressed air, traveling radially outward from the sourceat supersonic velocities. Only one-third of the chemical energyavailable in most high explosives is released in the detonationprocess. The remaining two-thirds is released more slowly as thedetonation products mix with air and burn. This afterburningprocess has little effect on the initial blast wave because it occursmuch slower than the original detonation. However, later stagesof the blast wave can be affected by the afterburning, particularlyEXPLOSIVE BLAST4-1
for explosions in confined spaces. As the shock wave expands,pressures decrease rapidly (with the cube of the distance) becauseof geometric divergence and the dissipation of energy in heatingthe air. Pressures also decay rapidly over time (i.e., exponentially)and have a very brief span of existence, measured typically inthousandths of a second, or milliseconds . An explosion can be visualized as a “bubble” of highly compressed air that expands untilreaching equilibrium with the surrounding air.Explosive detonations create an incident blast wave, characterizedby an almost instantaneous rise from atmospheric pressure to apeak overpressure. As the shock front expands pressure decaysback to ambient pressure, a negative pressure phase occurs thatis usually longer in duration than the positive phase as shown inFigure 4-1. The negative phase is usually less important in a designthan the positive phase.When the incident pressure wave impinges on a structure that isnot parallel to the direction of the wave’s travel, it is reflected andreinforced, producing what is known as reflected pressure. TheFigure 4-14-2Typical pressure-time historyEXPLOSIVE BLAST
reflected pressure is always greater than the incident pressureat the same distance from the explosion. The reflected pressure varies with the angle of incidence of the shock wave. Whenthe shock wave impinges on a surface that is perpendicular tothe direction it is traveling, the point of impact will experiencethe maximum reflected pressure. When the reflecting surfaceis parallel to the blast wave, the minimum reflected pressure orincident pressure will be experienced. In addition to the angle ofincidence, the magnitude of the peak reflected pressure is dependent on the peak incident pressure, which is a function of the netexplosive weight and distance from the detonation.Figure 4-2 shows typical reflected pressure coefficients versus theangle of incidence for four different peak incident pressures.The reflected pressure coefficient equals the ratio of the peak reflected pressure to the peak incident pressure (Cr Pr / Pi). Thisfigure shows that reflected pressures for explosive detonationsFigure 4-2Reflected pressure coefficient vs. angle of incidenceEXPLOSIVE BLAST4-3
can be almost 13 times greater than peak incident pressures and,for all explosions, the reflected pressure coefficients are significantly greater closer to the explosion.The integrated area under the pressure verse time function is knownas the impulse:I P(t)dtI impulse (psi-ms or Mpa-ms)P Pressure (psi or MPa)T time (ms)Impulse is a measure of the energy froman explosion imparted to a building.Both the negative and positive phases ofthe pressure-time waveform contributeto impulse. Figure 4-3 shows how impulse and pressure vary over time from atypical explosive detonation. The magnitude and distribution of blast loads on astructure vary greatly with several factors: Explosive properties (type of material, energy output, andquantity of explosive)Figure 4-34-4Typical impulse waveformEXPLOSIVE BLAST
Location of the detonation relative to the structure Reinforcement of the pressure pulse through its interactionwith the ground or structure (reflections)The reflected pressure and the reflected impulse are the forces towhich the building ultimately responds. These forces vary in timeand space over the exposed surface of the building, depending onthe location of the detonation in relation to the building. Therefore, when analyzing a structure for a specific blast event, careshould be taken to identify the worst case explosive detonationlocation.In the context of other hazards (e.g., earthquakes, winds, or floods),an explosive attack has the following distinguishing features: The intensity of the pressures acting on a targeted buildingcan be several orders of magnitude greater than these otherhazards. It is not uncommon for the peak incident pressure tobe in excess of 100 psi on a building in an urban setting for avehicle weapon parked along the curb. At these pressure levels,major damages and failure are expected. Explosive pressures decay extremely rapidly with distance fromthe source. Therefore, the damages on the side of the buildingfacing the explosion may be significantly more severe than onthe opposite side. As a consequence, direct air-blast damagestend to cause more localized damage. In an urban setting,however, reflections off surrounding buildings can increasedamages to the opposite side. The duration of the event is very short, measured inthousandths of a second, or milliseconds. This differs fromearthquakes and wind gusts, which are measured in seconds,or sustained wind or flood situations, which may be measuredin hours. Because of this, the mass of the structure has astrong mitigating effect on the response because it takes timeto mobilize the mass of the structure. By the time the mass ismobilized, the loading is gone, thus mitigating the response.EXPLOSIVE BLAST4-5
This is the opposite of earthquakes, whose imparted forces areroughly in the same timeframe as the response of the buildingmass, causing a resonance effect that can worsen the damage.4.1.1Building DamageThe extent and severity of damage and injuries in an explosiveevent cannot be predicted with perfect certainty. Past events showthat the unique specifics of the failure sequence for a building significantly affect the level of damage. Despite these uncertainties, itis possible to give some general indications of the overall level ofdamage and injuries to be expected in an explosive event, basedon the size of the explosion, distance from the event, and assumptions about the construction of the building.Damage due to the air-blast shock wave may be divided into directair-blast effects and progressive collapse. Direct air-blast effectsare damage caused by the high-intensity pressures of the air-blastclose in to the explosion and may induce the localized failure ofexterior walls, windows, floor systems, columns, and girders. A discussion of progressive collapse can be found in Chapter 3.The air blast shock wave is the primary damage mechanism in anexplosion. The pressures it exerts on building surfaces may beseveral orders of magnitude greater than the loads for which thebuilding is designed. The shock wave also acts in directions thatthe building may not have been designed for, such as upward onthe floor system. In terms of sequence of response, the air-blastfirst impinges on the weakest point in the vicinity of the deviceclosest to the explosion, typically the exterior envelope of thebuilding. The explosion pushes on the exterior walls at the lowerstories and may cause wall failure and window breakage. As theshock wave continues to expand, it enters the structure, pushingboth upward and downward on the floors (see Figure 4-4).Floor failure is common in large-scale vehicle-delivered explosiveattacks, because floor slabs typically have a large surface area forthe pressure to act on and a comparably small thickness. In terms4-6EXPLOSIVE BLAST
Figure 4-4Blast pressure effects on a structureSOURCE: NAVAL FACILITIES ENGINEERING SERVICE CENTER, USER’S GUIDE ON PROTECTION AGAINST TERRORIST VEHICLE BOMBS,MAY 1998of the timing of events, the building is engulfed by the shock waveand direct air-blast damage occurs within tens to hundreds of milliseconds from the time of detonation. If progressive collapse isinitiated, it typically occurs within seconds.EXPLOSIVE BLAST4-7
Glass is often the weakest part of a building, breaking at low pressures compared to other components such as the floors, walls,or columns. Past incidents have shown that glass breakage mayextend for miles in large external explosions. High-velocity glassfragments have been shown to be a major contributor to injuriesin such incidents. For incidents within downtown city areas, fallingglass poses a major hazard to passersby on the sidewalks below andprolongs post-incident rescue and cleanup efforts by leaving tonsof glass debris on the street. Specific glazing design considerationsare discussed in Chapter 3.4.1.2InjuriesSeverity and type of injury patterns incurred in explosive eventsmay be related to the level of structural damage. The high pressure of the air-blast that enters through broken windows can causeeardrum damage and lung collapse. As the air-blast damages thebuilding components in its path, missiles are generated that causeimpact injuries. Airborne glass fragments typically cause penetration or laceration-type injuries. Larger fragments may causenon-penetrating, or blunt trauma, injuries. Finally, the air-blastpressures can cause occupants to be bodily thrown against objectsor to fall. Lacerations due to high-velocity flying glass fragmentshave been responsible for a significant portion of the injuriesreceived in explosion incidents. In the bombing of the MurrahFederal Building in Oklahoma City, for instance, 40 percent ofthe survivors in the Murrah Federal Building cited glass as contributing to their injuries. Within nearby buildings, lacerationestimates ranged from 25 percent to 30 percent.4.1.3Levels of ProtectionThe amount of explosive and the resulting blast dictate the levelof protection required to prevent a building from collapsing orminimizing injuries and deaths. Table 4-1 shows how the DoD correlates levels of protection with potential damage and expectedinjuries. The GSA and the Interagency Security Committee (ISC)also use the level of protection concept. However, wherein theDoD has five levels, they have established four levels of protection.4-8EXPLOSIVE BLAST
Table 4-1: DoD Minimum Antiterrorism (AT) Standards for New Buildings*Level ofProtectionPotential Structural DamagePotential Door and GlazingHazardsPotential InjuryBelow ATstandardsSeverely damaged. Frame collapse/massive destruction. Little leftstanding.Doors and windows fail and result inlethal hazardsMajority of personnelsuffer fatalities.Very LowHeavily damaged - onset of structuralcollapse. Major deformation ofprimary and secondary structuralmembers, but progressive collapse isunlikely. Collapse of non-structuralelements.Glazing will break and is likely to bepropelled into the building, resultingin serious glazing fragment injuries,but fragments will be reduced.Doors may be propelled into rooms,presenting serious hazards.Majority of personnelsuffer serious injuries.There are likely to bea limited number (10percent to 25 percent) offatalities.Damaged – unrepairable.Glazing will break, but fall within1 meter of the wall or otherwisenot present a significant fragmenthazard. Doors may fail, but theywill rebound out of their frames,presenting minimal hazards.Majority of personnelsuffer significant injuries.There may be a few( 10 percent) fatalities.Glazing will break, but will remain inthe window frame. Doors will stay inframes, but will not be reusable.Some minor injuries, butfatalities are unlikely.Glazing will not break. Doors will bereusable.Only superficial injuriesare likely.LowMajor deformation of non-structuralelements and secondary structuralmembers, and minor deformationof primary structural members, butprogressive collapse is unlikely.MediumDamaged – repairable.Minor deformations of non-structuralelements and secondary structuralmembers and no permanentdeformation in primary structuralmembers.HighSuperficially damaged.No permanent deformation ofprimary and secondary structuralmembers or non-structural elements.* THE DoD UNIFIED FACILITIES CRITERIA (UFC), DoD MINIMUM ANTITERRORISM STANDARDS FOR BUILDINGS, UFC 4-010-01 31 JULY 2002The GSA and ISC levels of protection can be found in GSA PBS-P100, Facilities Standards for thePublic Buildings Service, November 2000, Section 8.6.EXPLOSIVE BLAST4-9
The levels of protection above can roughly be correlated for conventional construction without any blast hardening to the incidentpressures shown in Table 4-2.Table 4-2: Correlation of DoD Level of Protection to Incident PressureLevel of ProtectionIncident Pressure (psi)High1.1Medium1.8Low2.3Figure 4-5 shows an example of a range-to-effect chart that indicates the distance or stand-off to which a given size bomb willproduce a given effect (see Section 4.2). This type of chart canbe used to display the blast response of a building componentor window at different levels of protection. It can also be used toconsolidate all building response information to assess needed actions if the threat weapon-yield changes. For example, an amountof explosives are stolen and indications are that they may be usedagainst a specific building. A building-specific range-to-effect chartwill allow quick determination of the needed stand-off for theamount of explosives in question, after the explosive weight is converted to TNT equivalence.Research performed as part of the threat assessment processshould identify bomb sizes used in the locality or region. Securityconsultants have valuable information that may be used to evaluatethe range of likely charge weights. Given an explosive weight and astand-off distance, Figure 4-5 can beused to predict damage for nominalFor design purposes, large-scale truck bombs typically contain 10,000building construction.pounds or more of TNT equivalent, depending on the size and capacityof the vehicle used to deliver the weapon. Vehicle bombs that utilizevans down to small sedans typically contain 4,000 to 500 pounds of TNTequivalent, respectively. A briefcase bomb is approximately 50 pounds,and a pipe bomb is generally in the range of 5 pounds of TNT equivalent.4-10Figures 4-6 and 4-7 show blast effects predictions for a building basedon a typical car bomb and a typicallarge truck bomb detonated in theEXPLOSIVE BLAST
SOURCE: DEFENSE THREAT REDUCTION AGENCYFigure 4-5Explosives environments - blast range to effectsbuilding’s parking lot, respectively. A computer-based GeographicInformation System (GIS) was used to analyze the building's vehicular access and circulation pattern to determine a reasonabledetonation point for a vehicle bomb. Structural blast analysis wasthen performed using nominal explosive weights and a nominalbuilding structure. The results are shown in Figures 4-6 and 4-7.EXPLOSIVE BLAST4-11
Figure 4- 6Blast analysis of a building for a typical car bombdetonated in the building’s parking lotFigure 4-7Blast analysis of a building for a typical large truckbomb detonated in the building’s parking lot4-12EXPLOSIVE BLAST
The red ring indicates the area in which structural collapse ispredicted. The orange and yellow rings indicate predictions forlethal injuries and severe injuries from glass, respectively. Pleasenote that nominal inputs were used in this analysis and they arenot a predictive examination.In the case of a stationary vehicle bomb, knowing the size of thebomb (TNT equivalent in weight), its distance from the structure,how the structure is put together, and the materials used for walls,framing, and glazing allows the designer to determine the levelof damage that will occur and the level of protection achieved.Whether an existing building or a new construction, the designercan then select mitigation measures as presented in this chapterand in Chapters 2 and 3 to achieve the level of protection desired.4.2STAND-OFF DISTANCE AND THEEFFECTS OF BLASTEnergy from a blast decreases rapidly over distance. In general,the cost to provide asset protection will decrease as the distancebetween an asset and a threat increases, as shown in Figure 4-8.However, increasing stand-off also requires more land and moreperimeter to secure with barriers, resulting in an increasedcost not reflected in Figure 4-8. As stand-off increases, blastloads generated by an explosion decrease and the amount ofSOURCE: U.S. AIR FORCE, INSTALLATIONFORCE PROTECTION GUIDEFigure 4-8Relationship of cost to stand-off distanceEXPLOSIVE BLAST4-13
hardening necessary to provide the required level of protectiondecreases. Figure 4-9 shows how the impact of a blast will decreaseas the stand-off distance increases, as indicated in the blast analysisof the Khobar Towers incident. Increasing the stand-off distancefrom 80 to 400 feet would have significantly limited the damageto the building and hazard to occupants, the magnitude of whichis shown as the yellow and red areas in Figure 4-9. Additional concepts of stand-off distance are discussed in Section 2.3.The critical location of the weapon is a function of the site, thebuilding layout, and the security measures in place. For vehiclebombs, the critical locations are considered to be at the closestpoint that a vehicle can approach on each side, assuming that allsecurity measures are in place. Typically, this is a vehicle parkedalong the curb directly outside the building, or at the entry control point where inspection takes place. For internal weapons,location is dictated by the areas of the building that are publiclyaccessible (e.g., lobbies, corridors, auditoriums, cafeterias, orgymnasiums). Range or stand-off is measured from the center ofgravity of the charge located in the vehicle or other container tothe building component under consideration.Defining appropriate stand-off distance for a given building component to resist explosive blast effects is difficult. Often, in urbansettings, it is either not possible or practical to obtain appropriatestand-off distance. Adding to the difficulty is the fact that definingappropriate stand-off distance requires a prediction of the explosive weight of the weapon. In the case of terrorism, this is tenuousat best.The DoD prescribes minimum stand-off distances based on therequired level of protection. Where minimum stand-off distancesare met, conventional construction techniques can be used withsome modifications. In cases where the minimum stand-off cannotbe achieved, the building must be hardened to achieve the required level of protection (see Unified Facilities Criteria – DoDMinimum Antiterrorism Standards for Buildings, UFC 4-010-01,31 July 2002).4-14EXPLOSIVE BLAST
SOURCE: U.S. AIR FORCE, INSTALLATION FORCE PROTECTION GUIDEFigure 4-9Stand-off distance and its relationship to blast impact as modeled onthe Khobar Towers siteEXPLOSIVE BLAST4-15
The GSA and ISC Security Criteria do not require or mandatespecific stand-off distances. Rather, they provide protection performance criteria. In order to economically meet these performancestandards, they present recommended stand-off distances for vehicles that are parked on adjacent properties and for vehicles thatare parked on the building site (see GSA Security Criteria, Draft Revision, October 8, 1997, and ISC Security Design Criteria for New FederalOffice Buildings and Major Modernization Projects, May 28, 2001).Site and layout design guidance as well as specific mitigation measures to enhance stand-off and enhance protection from explosiveblast are discussed in Chapter 2.4.3PREDICTING BLAST EFFECTS4.3.1Blast Load PredictionsThe first step in predicting blast effects on a building is to predictblast loads on the structure. For a detonation that is exterior to abuilding, it is the blast pressure pulse that causes damage to thebuilding. Because the pressure pulse varies based on stand-off distance, angle of incidence, and reflected pressure over the exteriorof the building, the blast load prediction should be performed atmultiple threat locations; however, worse case conditions are normally used for decision-making.For complex structures requiring refined estimates of blast load,blast consultants may use sophisticated methods such as Computational Fluid Dynamics (CFD) computer programs to predict blastloads. These complex programs require special equipment andtraining to run.In most cases, especially for design purposes, more simplifiedmethods may be used by blast consultants to predict blast loads.The overpressure is assumed to instantaneously rise to its peakvalue and decay linearly to zero in a time known as the durationtime. In order to obtain the blast load, a number of differenttools can be used. Tables of pre-determined values may be used(see GSA Security Reference Manual: Part 3 – Blast Design & Assess4-16EXPLOSIVE BLAST
ment Guidelines, July 31, 2001) or computer programs may beused, such as: 1 ATBLAST (GSA) CONWEP (U.S. Army Engineer Research and DevelopmentCenter)SOURCE: U.S. AIR FORCE, INSTALLATION FORCE PROTECTION GUIDEFigure 4-10 provides a quick method for predicting the expectedoverpressure (expressed in pounds per square inch or psi) on abuilding for a specific explosive weight and stand-off distance.Enter the x-axis with the estimated explosive weight a terroristmight use and the y-axis with a known stand-off distance from abuilding. By correlating the resultant effects of overpressure withFigure 4-10Incident overpressure measured in pounds per square inch, as a function of stand-offdistance and net explosive weight (pounds-TNT)1For security reasons, the distribution of these computer programs is limited.EXPLOSIVE BLAST4-17
other data, the degree of damage that the various components ofa building might receive can be estimated. The vehicle icons inFigures 4-5 and 4-10 indicate the relative size of the vehicles thatmight be used to transport various quantities of explosives.4.3.2Blast Effects PredictionsAfter the blast load has been predicted, damage levels may be evaluated by explosive testing, engineering analysis, or both. Explosivetesting is actively conducted by Federal Government agenciessuch as the Defense Threat Reduction Agency, DOS, and GSA.Manufacturers of innovative products also conduct explosive testprograms to verify the effectiveness of their products.Often, testing is too expensive an option for the design communityand an engineering analysis is performed instead. To accuratelyrepresent the response of an explosive event, the analysis needs tobe time dependent and account for non-linear behavior.Non-linear dynamic analysis techniques are similar to those currently used in advanced seismic analysis. Analytical models rangefrom equivalent single-degree-of-freedom (SDOF) models tofinite element (FEM) representation. In either case, numericalcomputation requires adequate resolution in space and time to account for the high-intensity, short-duration loading and non-linearresponse. The main problems are the selection of the model, theappropriate failure modes, and, finally, the interpretation of theresults for structural design details. Whenever possible, results arechecked against data from tests and experiments on similar structures and loadings. Available computer programs include: AT Planner (U.S. Army Engineer Research and DevelopmentCenter) BEEM (Technical Support Working Group) BLASTFX (Federal Aviation Administration)Components such as beams, slabs, or walls can often be modeledby a SDOF system. The response can be found by using the charts4-18EXPLOSIVE BLAST
developed by Biggs and military handbooks. For more complexelements, the engineer must resort to numerical time integrationtechniques. The time and cost of the analysis cannot be ignoredin choosing analytical procedures. SDOF models are suitable fornumerical analysis on PCs and micro-computers, but the mostsophisticated FEM systems (with non-linear material models andoptions for explicit modeling of reinforcing bars) may have to becarried out on mainframes. Because the design analysis processis a sequence of iteration, the cost of analysis must be justified interms of benefits to the project and increased confidence in thereliability of the results. In some cases, an SDOF approach willbe used for the preliminary design and a more sophisticated approach, using finite elements, will be used for the final design.Table 4-3 provides estimates of incident pressures at whichdamage may occur.Table 4-3: Damage ApproximationsDamageIncidentOverpressure (psi)Typical window glass breakage0.15 – 0.22Minor damage to some buildings0.5 – 1.1Panels of sheet metal buckled1.1 – 1.8Failure of concrete block walls1.8 – 2.9Collapse of wood framed buildingsOver 5.0Serious damage to steel framed buildings4–7Severe damage to reinforced concrete structures6–9Probable total destruction of most buildings10 – 12SOURCE: EXPLOSIVE SHOCKS IN AIR, KINNEY & GRAHM, 1985; FACILITY DAMAGE ANDPERSONNEL INJURY FROM EXPLOSIVE BLAST, MONTGOMERY & WARD, 1993; AND THEEFFECTS OF NUCLEAR WEAPONS, 3RD EDITION, GLASSTONE & DOLAN, 1977EXPLOSIVE BLAST4-19
Additional sources of information: Air Force Engineering and Services Center. ProtectiveConstruction Design Manual, ESL-TR-87-57. Prepared forEngineering and Services Laboratory, Tyndall Air Force Base,FL. (1989). U.S. Department of the Army. Fundamentals of ProtectiveDesign for Conventional Weapons, TM 5-855-1. Washington, DC,Headquarters, U.S. Department of the Army. (1986). U.S. Department of the Army. Security Engineering, TM 5853 and Air Force AFMAN 32-1071, Volumes 1, 2, 3, and 4.Washington, DC, Departments of the Army and Air Force. (1994). U.S. Department of the Army. Structures to Resist the Effects ofAccidental Explosions, Army TM 5-1300, Navy NAVFAC P-397,AFR 88-2. Washington, DC, Departments of the Army, Navy,and Air Force. (1990). U.S. Department of Energy. A Manual for the Prediction ofBlast and Fragment Loading on Structures, DOE/TIC 11268.Washington, DC, Headquarters, U.S. Department of Energy.(1992). U.S. General Services Administration. GSA Security ReferenceManual: Part 3 Blast Design and Assessment Guidelines. (2001). Biggs, John M. Introduction to Structural Dynamics. McGrawHill. (1964). The Institute of Structural Engineers. The Structural Engineer’sResponse to Explosive Damage. SETO, Ltd., 11 Upper BelgraveStreet, London SW1X8BH. (1995). Mays, G.S. and Smith, P.D. Blast Effects on Buildings: Designof Buildings to Optimize Resistance to Blast Loading. ThomasTelford Publications, 1 Heron Quay, London E14 4JD. (1995). National Research Council. Protecting Buildings from BombDamage. National Academy Press. (1995).4-20EXPLOSIVE BLAST
EXPLOSIVE BLAST 4 EXPLOSIVE BLAST 4-1 This chapter discusses blast effects, building damage, inju- ries, levels of protection, stand-off distance, and predicting bla
FEMA P-320 and P-361 guidelines, FEMA’s term "safe room" can only be applied to protective spaces meeting the FEMA criteria. If a space is designed only to the ICC-500 Standard then FEMA requires it be called a “shelter”. Therefore: FEMA does not recognized NSSA/ICC 500 compliant safe rooms as meeting FEMA 361. They
blast furnaces whose Inner Volume exceeds 5,000m3. Figure 2: Comparison of fuel rate and productivity between Blast furnaces of NSE's and others 1.2 Features of large blast furnace and proposed technology In general, stable operation is difficult for large blast furnace, productivity and gas utilization falls as inner volume becomes larger.
Blast injuries occur through multiple mechanisms.12 13 15 1njuries directly related to the initial blast wave are referred to as primary blast injuries. In addition to primary injuries, the blast wind that follows the overpressure wave can propel objects including shrapnel contained within the lED, causing secondary injury.
ducing agents for blast furnace is approved under the provisions of this law. 2. Use as a reducing agent in blast furnaces 2.1 Blast furnaces As shown in Fig. 1, iron ore and coke are loaded into the blast furnace from the top in alternate layers, and hot air from the tuyeres at the base of the furnace fed in to generate CO gas from the coke .
tornado protection since 1980, in TR-83A FEMA was involved with the development of ICC 500, the first consensus code for storm shelters released in 2008 11 Latest in ICC 500 and FEMA P-361 Requirements FEMA-Funded Safe Room Grants 12 FEMA’s recommended guidance in P-320 and P-361 are r
FEMA Benefit-Cost Analysis Fundamentals FEMA Emergency Support Function #6: Mass Care, Emergency Assistance, Housing, and Human Services FEMA Fundamentals of Emergency Management FEMA Fundamentals of Risk Management FEMA ICS-2
FEMA GO User Manual Mitigation: Hazards 08/25/20 1 Introduction FEMA GO is one electronic application solution that houses the grant management functions for all of FEMA’s grant programs. This user manual addresses the Subapplication Development module for FEMA’s hazard mitigation grant programs.
Bob: Ch. 01Processes as diagrams Ch. 02String diagrams Ch. 03Hilbert space from diagrams Ch. 04Quantum processes Ch. 05Quantum measurement Ch. 06Picturing classical processes
